Chest

The Limited Scope ARRT Exam Chest Module is composed of 20 questions.  The focus of the question topics are listed below in the order of importance (from high to low) 

For radiographic projections, most of the questions will be on what we've gone over.  There may be one or two questions on subject matter that we have not gone over.  You may want to review these in your book so you are at least familiar with them.  The great thing about the chest exams is that centering it the same, no matter the exam.  If it's a PA projection, the CR will enter 7-8 inches below the vertebral prominens.  For AP projections, the CR will be 3-4 inches below the jugular notch.  Either way, it is at the level of T-7.  The radiographic positions and projections may include:


Reading - This is just suggested reading as you've already had these assigned during the previous course.  The intent is just to review.


Thorax anatomy review:

Ribs - 12 sets of ribs

Sternum - Divided into 3 parts

Lungs


Additional Info

Remember that body habitus will play a role in how to situate the image receptor (cassette).  If it is a hypersthenic patient, you will want to position the image receptor crosswise (14" x 17" size).  For Asthenic patients, you will want to put the IR in lengthwise.

Most of the time, you will want make the exposure during the second full inspiration.  This helps ensure the deepest inspiration possible, which will help the radiologist diagnose, and will also decrease the chance of repeats.  Remember that poor inspiration can mimic pathology, such as pneumonia.  There may be times when you may be asked to take 2 PA or AP views, one on inspiration and one on expiration.  In these cases, it may be to rule out a small pneumothorax (air in the pleural space, which is a sign of pathology), or to rule out a foreign body.

Generally chest imaging uses high mA settings and short exposure times.  Short exposure times are important to minimize motion.

Chest imaging, with the exception of ribs, is usually performed at a 72" SID.  The larger source to image distance has a few advantages.  Longer SID's mean reduced magnification.  It also means lower entrance skin exposures for the patient.  The one downfall, which isn't really a concern for modern x-ray machines, is that using longer SID's will require more mAs.  This just puts a little more strain on the x-ray machine.  The filaments within the x-ray tube have a lifespan, just like a light bulb does.